Site Considerations

One key element of deciding to build a renewable electricity project is identifying a suitable location for the project.

Assessing a potential site for a renewable electricity project involves considering the site’s technical, economic, policy, and other variables.

Available Sites and Project Types

When assessing a renewable electricity site and creating a list of possible project locations, consider the types of project options available and the site elements they would require. It can be useful to start by creating a list of several potential locations that could serve your project needs.

For instance, a solar photovoltaic project could be built atop a building with a large, flat roof (rooftop solar), on an expanse of available land near a building (ground-mounted solar), or on structures that shade a parking lot (solar canopy). Favorable solar sites have access to existing electrical infrastructure, southern exposure to direct sunlight, minimal shading, easy access to the physical project site, and site uses that do not interfere with the project.

Wind projects can range in size based on land availability and the number and size of turbines used. The quality of the wind resource at a site is critical as well. Wind speeds differ by region, but factors like elevation, density of vegetation, and proximity to water will affect the wind resource of a given site. The National Renewable Energy Laboratory (NREL) has resources that help to identify the quality of the wind resource at a given site. Proximity to electrical infrastructure is critical for a wind project, too. Like solar power, electricity generated from a wind project can be used on-site or off-site. In the case of wind projects, off-site purchasers of the power may be hundreds of miles away, in which case the proximity of transmission lines is a consideration for viable sites.

Technical Feasibility

A site must also have features that enable a project to be technically feasible. This includes a site’s physical and electrical infrastructure.

For a solar rooftop project, the age and condition of the roof is a key consideration. Solar systems typically have a lifespan of 20 to 30 years. If a roof replacement is needed during this timeframe, this means the solar array likely will need to be removed and reinstalled, which can add significantly to the project’s lifetime costs. For a solar ground-mounted system, a site with flat, clear ground will make installation easier, while the costs to grade an unlevel site can impact a project’s viability.

Building and site managers can provide information to help answer these questions.

Economic Considerations

Economic analysis of a potential project site is important to ensure that a project is financially viable. It may help to start by determining current energy use and spending by analyzing recent utility bills or consulting the local utility. A site’s estimated potential annual energy production is another important consideration.

Online tools can help with this assessment. The NREL REopt Lite tool can be used to compare current and potential energy generation. NREL’s PVWatts Calculator can quickly estimate how much a solar project in a particular location can yield. For wind, NREL and DOE offer a similar sets of tools. For example, the Wind Prospector allows users to view high-level siting issues with large-scale wind farms by providing easy access to GIS-based wind resource datasets and other data relevant to siting wind power projects.

Policy Considerations

Local, state, and federal policies can impact the selection of a project site. Building permitting, environmental permitting, setback requirements, and utility interconnection standards may impact where you are able to build a project, as well as the timelines for doing so.

Other policies might impact the incentives available to projects at different sites. For instance, in some cases, a rooftop or canopy solar project might be eligible for greater financial incentives than a project built on new “greenfield” land. Similarly, there may be economic benefits to siting a project on unused "brownfield” land. Some incentives may involve the transfer of the renewable energy certificates (RECs) generated from the project’s output. Note that surrendering these non-energy attributes will impact a customer’s ability to claim the use of renewable electricity from the project.

Additional policy information is available at the North Carolina Clean Energy Technology Center’s Database of State Incentives for Renewables & Efficiency, your state or city’s sustainability website, and your local utility’s website.

Additional Resources

There are many resources available in the Green Power Partnership’s Renewable Energy Project Development Resource Directory. Below are some tools from the Directory.

• REopt Lite – another NREL tool that evaluates the economic viability of grid-connected systems.
• PVWatts – another NREL tool that estimated the electricity production for a grid-connected system.
• Solar maps - Solar maps provide monthly average daily total solar resource information on grid cells.
• Municipal Solar Site Selection Tool (xlsm) – this Excel workbook from RMI aids in efficiently identify promising sites for solar photovoltaic (PV) installations